Electric soldering iron



Jan. 26, 1954 A SCHOENWALD 2,667,561

ELECTRIC SOLDERING IRON Filed April 5, 1952 Patented Jan. 26, 1954ELECTRIC SOLDERINGr` IRON Alexander Schoenwald, Grove City, Pa.,assignor to P. Wall Mfg. Company, Grove City, Pa., a corporation ofPennsylvania Application April s, 1952, sel-'iai No. 280,242

s claims. (c1. 21a-26) My invention relates to electrical solderingirons and is particularly suitable for use as a hand tool, wherein ahandle may have wired connection with an electrical line and carries, atits forward end, a welding tip that is internally heated by means of anelectrical resistor element.

One object of my invention is to provide an electric iron of thecharacter referred to, wherein the welding tip will not become heatedabove a desired degree, but will be maintained at a somewhat uniformdegree of heat after it has been brought up to operating temperature,`thereby avoiding the use of thermally-actuated switches such as those ofthe bimetallic type, the use of which not only results in somefluctuations in temperature, but they may also interfere with radionicdevices.

Another object of my invention is to provide a heating element inV awelding-iron tip that will more rapidly effect heat transfer from theresistance element to the tip, both by conduction and by radiation.

Still another object of my invention is to provide a soldering ironstructure which, while it has simplicity of design, is readilyadaptable, even in the eld, to use with both large and small heatingelements, through a simple ar rangement that permits substitution oftips of various capacities and conductors of various resistances, aswell as substitution of complete units that comprise holders, tips,resistor conductors and resistance heating elements.

A further object of my invention is to provide an assembly of solderingiron parts that are readily connectible and disconnectible with respectto a handle, to permit of substitutions and replacements, and whereinprovision is made for excluding moisture from the exterior of the holderfor the tip.

Still a further object of my invention is to provide a welding torchstructure wherein the resistors and their associated conductors areencased in clay-like insulating members, the members being divided intolongitudinally aligned sections, to thereby reduce danger of shatteringor breaking of clay-like insulators, and consequent avoidance of shortcircuiting or grounding of electrical current within the holder.

Figure 1 is a longitudinal sectional view through the soldering iron;Fig. 2 is a view taken on the line II-II of Fig. 1, and Fig. 3 is an enlarged sectional view through a portion of the tip of Fig. 1.

The iron can be used with either A. C. or D. C. current, and thestructure comprises a handle 4 of conventional form, a tip holder 5 anda tip 6 welded thereto at l, so that worn tips can readily be replaced,by breaking the weld 'l and attaching a new tip. The holder 5 extendsinto a sleeve 8 and is connected thereto by a collar 9 and a set screwI0. Aset screw Il connects the sleeve 8 to an insulator blockl l2 thathas a shoulder I3 which is engaged by a disc i4 which is connected tothe handle 4 by screws l5. Studs I6 are interposed between the disc I4and the handle, to provide an air space across which heat will not beradiated readily to the handle. The heating element proper comprisesy acrimped ribbon I'I of high heat resistance, such as a chrome alloy.Coiled resistance wires i8 that, may be of nickel alloy or some puremetal which has a higher temperature coefiicient than the ribbon, havestraight portions I9 welded or soldered to the ribbon Il, and at theirrear ends, are welded to terminal rods 20 which serve as plugs forsockets 2l. The sockets have connection through a switch 4a withconductor wires 22. When the set screw l0 is loosened, the tip structurecan be withdrawn from the sleeve 8. Other wires of differentconductivities and heating capacities can thus readily be substituted.

The ribbon l1 extends around the cuter end of a clay core 23 and liesagainst flattened sides of such core. The various crimps or pleats inthe ribbon have direct engagement with the inner surface of the tip 6,at many points, to thereby more effectively conduct heat to the tip.Also, the greatly increased radiating area afforded by the crimps resultin rapid heat transfer through radiation.

The stem portions I9 of the resistors I8 extend through clay bars 24 ofrelatively short length. The coils I8 are disposed in four tube-likeclay members 25 that have central partitions and are arranged inend-to-end relation. As heretofore indicated, the making of the members24 and 25 in transversely-divided sections will greatly reduce danger ofthese clay insulating members being shattered through impacts of thetorch, as when it falls to a iioor or is struck against a solid object.Short circuiting and grounding of current is thus avoided.

The terminal members 20 extend through a clay bushing 26 that is held inplace on the holder 5 by a gland 21 which is screw-threaded into theholder 5. Packing 28 of asbestos yarn or other suitable material iscontained at the inner end of the gland 21, to seal against entry ofmoisture into the holder 5. Metal bushings 29 are contained withinrecesses in the block and serve to compress packing cords 30 and thusprevent seepage of water along the terminal bars 20 to the interior ofthe structure. The bushings are held in place by a clay washer 3|.

The ribbon resistor l1 will quickly bring the tip 6 to solderingtemperature. The tip will be maintained at a desired temperature,because as the ribbon I1 andthe helical `coils I8 become heated, therewilly be increased resistance' by the coils to the 110W of current, thuspreventing excessive heating of the ribbon resistor. This is a result ofmaking the coils of metalwhichhas a higher temperature coeflicient thanthe ribbon, and therefore offers gradually :increasing resistance to the110W of electrical-current;until an equilibrium is reached as betweenpower and temperature, thus giving an approximately. ther mostaticcontrol without needing any moving parts.

By increasing or decreasing the lengths of the helices I8 relative tothesizesrof the ribbon 1.1,:a desired difference-in temperature.' willbeattained in the tip 6,for various classeszofffwork. Also, where .quickheating iscldesired, the. -helicesfwwill be' made shorter, toreduce.'resistancer toiovv4 of current to the element I1.

I claim as my invention:

1. An electrical soldering iron. comprising, a tubular holder, `asoldering. tip. carried :by` the forward end vof the.' holder;insulating. members within the holder and"having1perforations'rextendinglongitudinally thereon conductorl'zmembers protruding from therearendvof. the insulating members, vat the rear end off'thefholder, aresistance-type heating elementenclosed :within the tip, andconductorswithin` the Vperfor-ations and connecting the `first-.namedlconductor` elements to the resistance heating element; the said elementbeing of` ribbon form pleated'crosswise.

2, An electrical soldering iron vcomprising a 4 tubular holder, asoldering tip carried by the forward end of the holder, insulatingmembers within the holder and having perforations extendinglongitudinally thereof, conductor members protruding from the rear endof the insulating members, at the rear end of the holder, aresistancetype heating element in the tip, and resistance coils in thesaid perforations and connecting the conductors in series with theheating element, the coils being of higher temperature coeiiicient thanfthe heating element, and the heating element having pleats formedcrosswise therein, and the outer folds of the pleats having directengagementwith; the inner wall of the tip.

3.fAn electricalv heating device comprising a holder havinga'cylindrical cavity, a tip therefor, conductors `in the holder, a clayinsulating re ALEXANDER SCHOENWALD.

References' Cited inthe le of thisA patent UNITED STATES PATENTS NumberName Date 563,715 Grutting July 7, 1896 915,974 Leonard Mar. 23, 1909973,592 Van Aller Oct. 25, 1910 1,279,321 i Gardner Sept. 17, 19181,660,920 Fanger Feb'. 28, 1928 1,994,994 :Hampton Mar. 19, 19352,064,645 Abbott Dec. 15, 1936 2,464,147 Myers Mar. 8,.-1949 2,488,477Rapaport Nov. 15,` 1949 2.515.781 vLennox July 18, 1950

